1. Field of the Invention
This invention relates to a novel process for producing m-or p-aminobenzylamine, and more particularly it relates to a commercially advantageous process for producing the same.
Aminobenzylamine is an important material used as a curing agent for epoxy resins, a raw material for polyamides and polyimide and a raw material for intermediates for pesticides and pharmaceuticals.
2. Description of the Prior Art
As for aminobenzylamine, there have so far been known processes for producing it using nitrobenzaldehyde or nitrobenzonitrile as starting raw material. For example, as for the process using the former as starting raw material, the following ones have been known:
(i) A process wherein from m-nitrobenzaldehyde is derived nitrobenzylbromide, which is then reacted with potassium phthalimide to obtain N-(m-nitrobenzyl)-phthalimide which is then subjected to a two-stage reduction to obtain m-aminobenzylamine (yield: Ca. 20%) (N. Kornblum et al., J.Am. Chem. Co., 71, 2137(1949)).
(ii) A process wherein m-nitrobenzaldehyde is reacted with phenylhydrazine to obtain a hydrazone compound which is then subjected to catalytic reduction to obtain m-aminobenzylamine (yield: 60%) (A. Siddiqui et al, Synth Commn, 7, 71-78 (1977)).
(iii) From m-nitrobenzaldehyde is obtained m-nitrobenzaldoxime which is then subjected to high pressure catalytic reduction with Raney nickel catalyst to obtain m-aminobenzylamine (yield: 52%) (J.R. Griffith et al, NRL Report 6439)).
On the other hand, as for the process using the latter as starting raw material, the following ones have been known:
(iv) A process wherein p-aminobenzonitrile derived from p-nitrobenzonitrile is reduced with lithium aluminum hydride to obtain p-aminobenzylamine (yield: 37%) (N.C. Brown et al, J. Medicinal Chem., 20, 1189 (1977)).
(v) A process wherein M-nitrobenzonitrile is subjected to high pressure catalytic reduction with Raney nickel catalyst to obtain m-aminobenzylamine (yield: 49%) (J.R. Griffith et al., NRL Report 6439)).
However, according to the above processes (i) and (ii), a relatively expensive compound such as potassium phthalimide or phenylhydrazine is used in an amount of equivalent or more to prepare an intermediate which is then reduced to obtain the objective compound, but these processes are not economical since the reaction process is long or cost and labor are required for recovering by-products. Further the process (iv) also has drawbacks that the reducing agent is not only expensive, but also difficult to deal with, still further, in the case of the processes and (v) wherein high pressure catalytic reduction is carried out in an autoclave with Raney nickel catalyst it is necessary to employ an expensive apparatus in order to raise the yield. Particularly the process (iii) has an additional disadvantage that the reaction process is prolonged since it is carried out via an aldoxime as an intermediate, and further hydroxylamine used in the preparation of this aldoxime is also relatively expensive.